Anti-Viral Agents

Question 1

Drugs used for chemoprophylaxis influenza

Answer 1

Amantadine

Rimantadine

Question 2

Amantadine (Symmetrel) is used for tx of Parkinson’s disease and excreted largely unchanged in urine,

Answer 2

True

Question 3

4-10x more active than amantadine and it has fewer side-effects due to extensive biotransformation

Answer 3

Rimantadine (Flumadine)

Question 4

Mechanism of action of Amantadine and Rimantadine.

Answer 4

• Inhibit viral uncoating
• Interferes with hemagglutinin processing which inhibits viral assembly
• Interferes with M2 protein

Question 5

Uses of drugs for chemoprophylaxis influenza

Answer 5

Tx of influenza type A
Seasonal tx with 70-90% protection against Type a
Not effective to type B

Question 6

Drugs acts as Neuraminidase Inhibitors

Answer 6

Oseltamivir, Zanamivir

Question 7

MOA of Neuraminidase Inhibitor Drugs

Answer 7

Inhibits neuraminidase which prevents enhancing of penetration of viruses to host cells = the viruses tend to aggregate and migration of viruses to host cells are inhibited

Question 8

Uses of Neuraminidase Inhibitor Drugs

Answer 8

Effective against Influenza types A and B

Question 9

Effective for pre and post exposure to Influenza virus and used as a dry powder for oral inhalation.

Answer 9

Zanamivir

Question 10

A prodrug in ethyl ester form and the first effective drug against influenza types A and B

Answer 10

Oseltamivir

Question 11

These are extremely potent cytokines with antiviral, immunomodulating and antiproliferative actions which is synthesized by infected cells in response to inducers which elicit antiviral state or natural killer cell response

Answer 11

Interferons

Question 12

Two interferons drugs

Answer 12

Interferon alfa
Interferon beta (Betaseron)

Question 13

Use of Interferons

Answer 13

With broad spectrum anti-viral activity against DNA and RNA viruses

Question 14

Interferons are not orally available, thus given IM/SC/topical or nasal spray.

T or F

Answer 14

True

Question 15

Nucleoside Antimetabolites are inhibitors of DNA Polymerase

Answer 15

True

Question 16

Nucleoside antimetabolite introduced for treatment of herpes simplex keratitis in 1963.

Answer 16

Idoxuridine

Question 17

MOA of Idoxuridine

Answer 17

Inhibits replication of DNA viruses such as herpesvirus, poxvirus

Phosphorylated to triphosphate form which inhibits viral DNA synthesis by inhibiting viral DNA polymerase and leads to strand breakage and faulty transcription

Question 18

Iodinated analog of thymidine

Answer 18

Idoxuridine

Question 19

Pyrimidine nucleoside, related to Idoxuridine used for the treatment of shingles, herpetic keratitis, Idoxuridine resistant-viral infections.

Answer 19

Cytarabine

Question 20

MOA of cytarabine

Answer 20

Phosphorylated to triphosphate form which blocks DNA polymerase and blocks cellular utilization of deoxycytidine which inhibits viral DNA replication

Question 21

Trifluorinated pyrimidine nucleoside with inhibitory action against HSV-1 and HSV-2, CMV, vaccinia, adenovirus.

Answer 21

Trifluridine

Question 22

The following statements are NOT true about Trifluridine, EXCEPT:

I. Has brand name Viroptic
II. Tx of primary keratoconjunctivitis, recurrent epithelial keratitis by HSV 1 and 2
III. For Acyclovir-resistant HSV infections

a. III only
b. I only
c. I, II, III
d. NOTA

Answer 22

c. I, II, III

Question 23

MOA of Trifluridine

Answer 23

Triphosphate form inhibits thymidine triphosphate incorporation into DNA by DNA polymerase = fragile, poorly functioning viral DNA

Question 24

Obtained from Streptomyces antibioticus and is used an alternative to Idoxuridie for tx of HSV keratitis and encephalitis.

Answer 24

Vidarabine

Question 25

MOA of Vidarabine

Answer 25

Activity confined to DNA viruses – triphosphate form competes with deoxyadenosine triphosphate for viral DNA polymerase

Question 26

L-valyl ester of acyclovir and increases BA by increasing lipophilicity.

Answer 26

Valacyclovir

Question 27

T or F Valacyclovir is used as tx of shingles in immunocompromised patient.

Answer 27

True

Question 28

Nucleoside antimetabolite that is administered orally and parenterally which is used for the treatment of herpesvirus infections.

Answer 28

Acyclovir

Question 29

Acyclovir is most active against HSV-1, 2x less active to HSV-2, 10x less potent to VZV. Uninfected human cells are unaffected by acyclovir. a. First statement is correct. b. Second statement is correct. c. Both statements are correct. d. Both statements are incorrect.

Answer 29

C.

Question 30

Orally active prodrug for chronic form of Hepatitis B

Answer 30

Adefovir

Question 31

Its diphosphate form inhibits Hepatitis B Virus DNA polymerase

Answer 31

Dipivoxil

Question 32

Analog of acyclovir and used against Herpes simplex viruses, Varicella-Zoster Virus (VZV), and Cytomegalovirus.

Answer 32

Ganciclovir

Question 33

MOA of Ganciclovir

Answer 33

Triphosphate form inhibits DNA polymerase and is incorporated into viral DNA leading to strand breakage and cessation of elongation

Question 34

The use Ganciclovir is limited because it causes myelosuppression such as neutropenia, thrombocytopenia, anemia. T or F

Answer 34

True

Question 35

100-fold less potent than acyclovir and tx for HSV I and 2

Answer 35

Penciclovir

Question 36

The triphosphate form of this drug is a competitive inhibitor of viral DNA polymerase

Answer 36

Penciclovir

Question 37

Diacetyl inactive prodrug thus lacks antiviral activity

Answer 37

Famciclovir

Question 38

A nucleoside antimetabolite with high therapeutic index against Cytomegalovirus (CMV)

Answer 38

Cidofovir

Question 39

MOA of Cidofovir

Answer 39

Diphosphate form is a competitive inhibitor of viral DNA polymerase and is incorporated into growing viral DNA strand causing DNA chain termination

Question 40

Cidofovir has dose-limiting toxicity that can lead renal impairment, so it must be given with rehydration and probenecid. T or F

Answer 40

True

Question 41

A nucleoside antimetabolite with synergistic activity with Zidovudine and Didanosine.

Answer 41

Foscarnet sodium

Question 42

Second line for CMV in AIDS patient

Answer 42

Foscarnet sodium

Question 43

MOA of Foscarnet sodium

Answer 43

No significant intracellular metabolism – reversible non competitive inhibitor of pyrophosphate binding site of